The present invention relates to a head gimbal assembly (HGA) including a suspension and a magnetic head slider provided with at least one thin-film magnetic head element and mounted on the suspension, used in for example a hard disk drive unit (HDD).
In an HDD, thin-film magnetic head elements for writing magnetic information into and/or reading magnetic information from magnetic disks are in general formed on magnetic head sliders flying in operation above the rotating magnetic disks. The sliders are supported at top end sections of suspensions of HGAs, respectively.
In each suspension, one ends of a plurality of signal lines are electrically connected to a plurality of terminal electrodes of at least one thin-film magnetic head element formed on the magnetic head slider, respectively. The signal lines run along the suspension, and the other ends of these signal lines are electrically connected to external connection pads formed on the back end section or outside of the suspension, respectively.
Recently, a suspension using no lead wire for the signal lines, that is, a wireless suspension or a suspension using a flexible print circuit (FPC) has spread.
The wireless suspension may be configured by directly depositing a pattern of sequentially laminated resin layer, trace conductor layer and resin layer on the suspension as for signal lines, or by adhering to the suspension a separated stainless steel plate on which sequentially laminated resin layer, trace conductor layer and resin layer are preliminarily formed.
The suspension with FPC is configured by adhering on a normal suspension a FPC fabricated by forming trace conductors on a resin base layer and by forming a resin overcoat layer on the resin base layer to cover the trace conductors.
However, if an HGA is configured using a wireless suspension, because the wireless suspension itself is expensive in comparison with a normal suspension, the manufacturing cost of the HGA becomes extremely high.
If an HGA is configured using a suspension with FPC, although the HGA can be cheaply fabricated, a flying performance of the magnetic head slider will greatly deteriorate due to a large stiffness of the FPC. Particularly, since a recent micro magnetic head slider with for example a width of about 0.7 mm, a height of about 0.23 mm and a length of about 0.87 mm has an extremely small ABS area, if a spring constant of the suspension increases due to the high stiffness of the FPC, a good flying performance cannot be expected at all. Furthermore, the conventional HGA configured using a suspension with FPC is very weak to side winds due to its large thickness, and this exerts an influence upon the action of the suspension in operation.
It is therefore an object of the present invention to provide an HGA, whereby a low manufacturing cost can be attained and also a good flying performance can be expected even if a micro magnetic head slider is mounted thereon.
Another object of the present invention is to provide an HGA, whereby a low manufacturing cost can be attained and also a stable flying performance substantially unaffected by side winds can be expected.
According to the present invention, an HGA includes
a magnetic head slider with at least one thin-film magnetic head element, a support with a top end section fixed to the magnetic head slider, and a FPC member with trace conductors. One ends of the trace conductors are electrically connected to terminal electrodes of the at least one thin-film magnetic head element. The FPC member further includes a resin layer intimately fixed to a surface of the support with an adhesive, which resin layer has a thickness of 12.7 xcexcm or less, and a trace conductor layer formed on the resin layer.
Since the resin layer such as a polyimide layer has an extremely thin thickness of 12.7 xcexcm (0.5 mil) or less, stiffness of the FPC member can be greatly lowered. As a result, an excellent flying performance of the magnetic head slider can be expected even if it is a micro magnetic head slider, and also it is used in a high-spindle rotation HDD. Furthermore, since the FPC member is thin and is intimately fixed to a surface of the support with the adhesive, it is possible to greatly decrease an influence of side winds resulting that a stable flying performance of the slider can be obtained. Thus, the HGA is adaptable to a high recording density HDD. It is a matter of course that using of the FPC as signal lines will provide an extremely cheap manufacturing cost in comparison with using of a wireless suspension.
It is preferred that both side edges of the FPC member are sealed with the adhesive. Thus, an influence of side winds with respect to the FPC member can be more reduced.
It is preferred that the support includes a base plate, a resilient hinge, a load beam coupled with the base plate through the hinge and a resilient flexure fixed to a top end section of the load beam, for mounting the magnetic head slider, or includes a base plate, a load beam coupled with the base plate and a resilient flexure fixed to a top end section of the load beam, for mounting the magnetic head slider.
It is also preferred that a part of the FPC member is intimately fixed to a surface of the flexure, and that the part of the FPC member only consists of the resin layer and the trace conductor layer formed on the resin layer.
It is further preferred that a part of the FPC member is intimately fixed to a surface of the load beam, and that the part of the FPC member consists of the resin layer, the trace conductor layer formed on the resin layer and an overcoat layer formed to cover the trace conductor layer.
It is preferred that the resin layer is a polyimide layer.
It is preferred that the end of the trace conductors is ball bonded with the terminal electrodes of the at least one thin-film magnetic head element.
In an embodiment according to the present invention, the magnetic head slider may be a micro magnetic head slider with a width of 1.0 mm or less, a height of 0.3 mm or less and a length of 1.0 mm or less.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.